fix IPv4/IPv6 listening port

whoops, it's "::" (the unspecified address), not "::1" (the loopback address)

refs #12

src/wormhole_transit_relay/server_tap.py

@@ -19,7 +19,7 @@ class Options(usage.Options):
     longdesc = LONGDESC
 
     optParameters = [
-        ("port", "p", "tcp:4001:interface=\:\:1", "endpoint to listen on"),
+        ("port", "p", "tcp:4001:interface=\:\:", "endpoint to listen on"),
         ("blur-usage", None, None, "blur timestamps and data sizes in logs"),
         ("log-fd", None, None, "write JSON usage logs to this file descriptor"),
         ("usage-db", None, None, "record usage data (SQLite)"),

src/wormhole_transit_relay/test/test_config.py

@@ -2,7 +2,7 @@ from __future__ import unicode_literals, print_function
 from twisted.trial import unittest
 from .. import server_tap
 
-PORT = "tcp:4001:interface=\:\:1"
+PORT = "tcp:4001:interface=\:\:"
 
 class Config(unittest.TestCase):
     def test_defaults(self):